Chloride salts have been applied on roads to inhibit the accumulation of snow and ice for many years. Such chloride salts may be applied to the surface of the road directly in solid form or in admixture with water or some other liquid. Spreaders, for instance, may apply solid or liquid de-icing compositions somewhat evenly over the surface of roads. Other substances, such as sand, may also be applied to the road with the solid or liquid composition having chloride salts to treat the roads and help reduce slipping on the road.
Brine solutions that contain high concentrations of earth metal and chloride ions are commonly used for application to roads. As long as the concentration of ions in the brine solution remains high enough, the solution remains in a liquid form and is useful as a de-icer. Once the solution is diluted below a critical ion concentration for a specific temperature, ice crystals begin to form in the solution and it is no longer useful as a de-icer.
Chloride salts and brine solutions have numerous problems as road de-icers. A first problem is that typical brine solutions containing chloride salts do not exhibit useful melting properties below, at the lowest, about −5 deg. F. A second problem is that such brine solutions impact the environment in negative ways. They may damage the soil and vegetation surrounding the road, in large part because of the salts, they may adversely impact surrounding lakes, rivers, or streams, and the compounds may be absorbed into water supplies. A final problem is that such brine solutions may exhibit corrosive effects, damaging vehicles on roads as well as the structure of the roads themselves. Many states have therefore limited the use of salt on roads.
De-icing compositions and methods have been developed that partially solve some of the above problems of prior de-icing compositions and methods. U.S. Pat. No. 4,676,918 to Toth et al., for instance, discloses an anti-freeze composition for prohibiting the buildup of snow and ice that contains, as a primary component, a waste concentrate of the alcohol distilling industry. U.S. Pat. Nos. 5,635,101; 5,709,812; and 5,709,813, all of which name Janke et al. as inventors, disclose the use of steepwater solubles from the wet milling process for corn, whey, and wine making residue respectively as the primary ingredients in de-icing compositions. According to these patents, the compositions disclosed therein provide environmental and corrosive-inhibiting benefits over salt de-icers.
These prior art de-icing compositions also have numerous disadvantages and problems. The freezing point of such de-icing compositions are typically not as low as may be desirable. Such compositions may contain a higher level of insoluble material than is desirable, which makes it more difficult to mix into liquid de-icers which may be easily spread onto roads. These de-icing compositions may also contain materials that may be harmful to the environment. For instance, some steepwater solubles compositions contain a large amount of phosphorus, which may be harmful to the environment. Typical steepwater solubles de-icing compositions have a pH around 3.0. Because a neutral pH (7.0) or a pH as close to neutral as possible is desirable for the environment, such steepwater solubles de-icing compositions may harm the environment.
An improved de-icing composition and method is needed that is environmentally safe, has a low freezing point and thus melts a large amount of snow and ice by suppressing ice crystal formation, exhibits low corrosive effects, and that maintains a high viscosity at low temperatures. Such a de-icing composition and method preferably solves the above problems of prior art de-icing compositions and is inexpensive to produce in large quantities.